Figure 1.

(A) Time-resolved fluorescence anisotropy decays of a single-Trp variant of β₂-microglobulin (Trp-95) in the native state (red solid circles), indicating local and global motions, and in the denatured state (4 M guanidine hydrochloride) (blue solid circles), indicating the segmental motion of the unfolded state. The black solid lines are anisotropy decay fits. For details of data acquisition and analysis, see Materials and Methods. See Fig. S1 for anisotropy decay of a free fluorophore in water and in a glycerol-water mixture. (B) Schematic of backbone torsional mobility of an unfolded polypeptide chain in the ϕ-ψ dihedral space. To see this figure in color, go online.